SYDNEY—Australian home lending in August expanded at its fastest annual pace since early 2018 as buyers borrowed ever more to get into a red-hot market, foreshadowing tougher rules from regulators concerned at the mounting risks to financial stability. Figures from the Reserve Bank of Australia (RBA) on Thursday showed outstanding home loans rose 0.6 percent in August, from July, lifting annual growth to 6.2 percent. That was the biggest annual rise since February 2018 and double the pace seen a year ago. Record-low mortgage rates have fueled the surge in debt, which in turn has inflated house prices. Annual price growth hit an eye-watering 18.4 percent in August, the fastest pace since July 1989 and a gain of A$1,990 ($1,444) per week for the median property, according to property consultant CoreLogic. With prices rising far faster than incomes, policy makers are concerned borrowers are taking on ever-larger amounts of debt, …